In a storage system, there is a case of creating a clone of a certain logical volume (primary volume).
For example, in PTL 1, the storage system includes a flash package group configured with a plurality of flash packages and a storage controller coupled to each of the flash packages. A generation number for identifying a difference volume that stores difference data between data in another volume and data in a primary volume, in addition to a write destination address, are associated with a write request from the storage controller to each of the flash packages. Each of the flash packages manages latest data of the same address by generation.
Further, for example, in PTL 2, the storage controller stores data in a cache memory before storing data in a drive.